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3.
Sci Rep ; 6: 26911, 2016 05 27.
Artigo em Inglês | MEDLINE | ID: mdl-27229325

RESUMO

A new specimen of the bizarrely specialised Malleodectes mirabilis from middle Miocene deposits in the Riversleigh World Heritage Area provides the first and only information about the molar dentition of this strange group of extinct marsupials. Apart from striking autapomorphies such as the enormous P3, other dental features such as stylar cusp D being larger than B suggest it belongs in the Order Dasyuromorphia. Phylogenetic analysis of 62 craniodental characters places Malleodectes within Dasyuromorphia albeit with weak support and without indication of specific relationships to any of the three established families (Dasyuridae, Myrmecobiidae and Thylacinidae). Accordingly we have allocated Malleodectes to the new family, Malleodectidae. Some features suggest potential links to previously named dasyuromorphians from Riversleigh (e.g., Ganbulanyi) but these are too poorly known to test this possibility. Although the original interpretation of a steeply declining molar row in Malleodectes can be rejected, it continues to seem likely that malleodectids specialised on snails but probably also consumed a wider range of prey items including small vertebrates. Whatever their actual diet, malleodectids appear to have filled a niche in Australia's rainforests that has not been occupied by any other mammal group anywhere in the world from the Miocene onwards.


Assuntos
Fósseis/anatomia & histologia , Marsupiais/classificação , Maxila/anatomia & histologia , Dente Molar/anatomia & histologia , Filogenia , Animais , Evolução Biológica , Carnivoridade/fisiologia , Dieta/história , Extinção Biológica , Fósseis/história , História Antiga , Marsupiais/anatomia & histologia , Marsupiais/fisiologia , Maxila/fisiologia , Dente Molar/fisiologia , Queensland
4.
Clin Microbiol Infect ; 20(6): O384-9, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24118354

RESUMO

Few data are available on the nephrotoxic potential of vancomycin when combined with certain ß-lactam antibiotics for the treatment of osteomyelitis (OM). A retrospective cohort study was conducted of all diabetic patients with OM treated with vancomycin plus piperacillin-tazobactam (VPT) or vancomycin plus cefepime (VC) for at least 72 h at a VA Medical Center between 1 January 2006 and 31 December 2011. All patients with a creatinine clearance (CrCl) of ≤ 40 mL/min, a blood urea nitrogen/serum creatinine (SCr) ratio of ≥ 20 : 1 or an absolute neutrophil count of <500 cells/mm(3) were excluded. The primary outcome was development of acute renal failure (ARF), defined as an increase in SCr of 0.5 mg/dL or 50% of baseline. One hundred and thirty-nine patients met the inclusion criteria; 109 in the piperacillin-tazobactam group and 30 in the cefepime group. Among patients receiving VPT, 29.3% (32/109) developed ARF, as compared with 13.3% (4/30) receiving VC (p 0.099). Among patients receiving high-dose therapy (≥ 18 g of piperacillin-tazobactam daily or ≥ 3 g of cefepime daily), 37.5% (9/24) receiving VPT and 17.6% (3/17) receiving VC developed ARF (p 0.29). A multiple logistic regression analysis identified weight and average vancomycin trough as the only significant predictors of ARF; the choice of VPT as therapy yielded an OR of 3.45 (95% CI 0.96-12.40; p 0.057). The authors were unable to detect a statistically significant difference in ARF between groups; however, the power requirement was not met. Further study with a larger patient population seems warranted.


Assuntos
Injúria Renal Aguda/induzido quimicamente , Antibacterianos/efeitos adversos , Cefalosporinas/efeitos adversos , Complicações do Diabetes/tratamento farmacológico , Osteomielite/tratamento farmacológico , Ácido Penicilânico/análogos & derivados , Vancomicina/efeitos adversos , Antibacterianos/uso terapêutico , Cefepima , Cefalosporinas/uso terapêutico , Estudos de Coortes , Quimioterapia Combinada/efeitos adversos , Quimioterapia Combinada/métodos , Humanos , Incidência , Pessoa de Meia-Idade , Ácido Penicilânico/efeitos adversos , Ácido Penicilânico/uso terapêutico , Piperacilina/efeitos adversos , Piperacilina/uso terapêutico , Combinação Piperacilina e Tazobactam , Estudos Retrospectivos , Vancomicina/uso terapêutico
5.
J Clin Microbiol ; 51(9): 3132-6, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23824776

RESUMO

Five laboratory-acquired brucellosis (LAB) cases that occurred in the United States between 2008 and 2011 are presented. The Centers for Disease Control and Prevention (CDC) reviewed the recommendations published in 2008 and the published literature to identify strategies to further prevent LAB. The improved prevention strategies are described.


Assuntos
Brucelose/diagnóstico , Brucelose/prevenção & controle , Controle de Infecções/métodos , Exposição Ocupacional , Adulto , Criança , Feminino , Pessoal de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Estados Unidos
6.
Br J Dermatol ; 168(6): 1339-42, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23301666

RESUMO

BACKGROUND: Eczema is common in infancy; however, there is little evidence about its natural history to adulthood. OBJECTIVES: To study the natural history of eczema from birth to young adult life with particular reference to its relation to atopy. METHODS: A birth cohort of children with atopic family histories was followed for 23 years. Clinical examinations were conducted until the age of 7 years, skin-prick tests and serum total IgE were recorded in infancy and at ages 7 and 23 years, and questionnaires about eczema symptoms were completed at 15 and 23 years. RESULTS: Information was obtained on 497 subjects at birth, 482 at 1 year, 440 at 7 years, 363 at 15 years and 304 at 23 years. Eczema usually remitted from age 1 to 7 years but became more persistent from the age of 15 years, especially in those who were atopic. The prevalence of eczema rose in women from age 15 to 23 years but declined in men. Adults with eczema had higher IgE than those without at 3 months (geometric mean 3·0 vs. 1·7 kU L(-1); P=0·01), 7 years (107·9 vs. 45·2 kU L(-1); P=0·01) and 23 years (123·4 vs. 42·3 kU L(-1); P=0·01), and were more likely to have had positive skin-prick tests at 1 year of age. Current eczema was associated with raised IgE in infancy and adulthood but not in childhood. CONCLUSIONS: Predisposed infants and children with eczema usually grow out of the disease, but in adolescence it is more likely to persist. Adult eczema is related to atopy from the age of 3 months.


Assuntos
Eczema/diagnóstico , Imunoglobulina E/imunologia , Adolescente , Fatores Etários , Criança , Pré-Escolar , Estudos de Coortes , Eczema/imunologia , Feminino , Seguimentos , Humanos , Lactente , Masculino , Prevalência , Índice de Gravidade de Doença , Fatores Sexuais , Testes Cutâneos , Inquéritos e Questionários , Adulto Jovem
7.
Clin Exp Allergy ; 34(5): 720-4, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-15144462

RESUMO

BACKGROUND: Peanuts and tree nuts are among the most common foods provoking severe allergic reactions including fatal anaphylaxis. However, little is known of the underlying genetic and immunological mechanisms involved. OBJECTIVE: Based on findings in other allergic diseases, we have investigated whether specific human leucocyte antigens (HLA) are associated with nut allergy. METHOD: Eighty-four patients presenting at the allergy clinic with symptoms of nut allergy were typed for the HLA Class I (HLA-A and B) and Class II (HLA-DRB1 and DQB1) loci by PCR using sequence-specific primers. Carriage frequencies were compared with 82 atopic non-nut-allergic subjects and 1798 random blood donors. RESULTS: The frequency of HLA-B(*)07 (28.57%) and DRB1(*)11 (15.48%) was increased in the nut-allergic patients compared to the atopic controls (12.20% and 3.66%, respectively) but not when compared to the blood donors (28.86% and 10.12%). DRB1(*)13 and DQB1(*)06 were both increased in frequency in the nut allergy patients over both the atopic and blood donor controls. However, none of these increased frequencies were significant when corrected for the number of comparisons undertaken. CONCLUSION: At HLA '2-digit resolution' and with undifferentiated patients with nut allergy, there are no major disturbances in the frequency of HLA-A, B, DRB1 or DQB1 types. However, the difference in frequency of HLA-DRB1(*)11 between the nut allergy patients and the atopic controls merits further investigation as this may represent an important phenotypic relationship.


Assuntos
Genes MHC da Classe II , Genes MHC Classe I , Hipersensibilidade a Noz/genética , Hipersensibilidade a Noz/imunologia , Polimorfismo Genético , Adolescente , Adulto , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Frequência do Gene , Predisposição Genética para Doença , Antígenos HLA-DQ/genética , Cadeias beta de HLA-DQ , Antígenos HLA-DR/genética , Cadeias HLA-DRB1 , Humanos , Masculino , Pessoa de Meia-Idade , Hipersensibilidade a Noz/diagnóstico , Testes Cutâneos
8.
Epidemiol Infect ; 132(2): 273-81, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15061502

RESUMO

Salmonella Javiana is a Salmonella serotype that is restricted geographically in the United States to the Southeast. During the summer of 2001, the number of reported S. Javiana infections in Mississippi increased sevenfold. To identify sources of infection, we conducted a case-control study, defining a case as an infection with S. Javiana between August and September in a Mississippi resident. We enrolled 55 cases and 109 controls. Thirty (55%) case patients reported exposure to amphibians, defined as owning, touching, or seeing an amphibian on one's property, compared with 30 (29%) controls (matched odds ratio 2.8, P=0.006). Contact with amphibians and their environments may be a risk factor for human infection with S. Javiana. The geographic pattern of S. Javiana infections in the United States mimics the distribution of certain amphibian species in the Southeast. Public health officials should consider amphibians as potential sources of salmonellosis, and promote hand washing after contact with amphibians.


Assuntos
Anfíbios/microbiologia , Infecções por Salmonella/etiologia , Salmonella enterica/isolamento & purificação , Adolescente , Adulto , Idoso , Animais , Estudos de Casos e Controles , Criança , Pré-Escolar , Reservatórios de Doenças , Humanos , Pessoa de Meia-Idade , Saúde Pública , Salmonella enterica/classificação , Sorotipagem
9.
Thorax ; 57(8): 715-8, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12149533

RESUMO

BACKGROUND: Smoking is a major public health issue, estimated as causing 120 000 deaths in the UK per year. Smoking cessation is an important aspect of the treatment of many diseases. Nicotine replacement therapy (NRT) has been shown to increase cessation rates among healthy volunteers and in general practice, but it is not clear whether it has an effect in hospital patients. METHODS: Patients referred by their hospital doctor to the smoking cessation counsellor and who agreed to participate in the study were randomised to receive either NRT given as a nicotine patch daily and a nicotine inhalator on an as needed basis plus advice and support (AS+NRT), or to receive just advice and support (AS). Claims of smoking cessation were validated at 1 week, 3 months, 6 months, and 1 year by carbon monoxide (CO) breath testing. RESULTS: A total of 245 patients were randomised, 136 AS+NRT and 109 AS. There were no significant demographic differences between the two groups at baseline. At 1 year 35 (14%) had sustained cessation confirmed by a CO breath test, 20/136 (15%) AS+NRT and 15/109 (14%) AS, p=0.857. One hundred and ten patients gave up smoking for at least 1 week, 54% AS+NRT and 33% AS (p<0.001). By 6 months there was no significant difference between the two groups (22/136 (16%) AS+NRT and 15/109 (14%) AS). CONCLUSION: In hospital patients NRT, given as regular daily patches plus an inhalator to be used as needed, did not add to the smoking cessation rate achieved at 1 year by regular advice and support, despite significantly increasing the cessation rate at 1 week.


Assuntos
Nicotina/administração & dosagem , Agonistas Nicotínicos/administração & dosagem , Abandono do Hábito de Fumar/métodos , Administração Cutânea , Administração por Inalação , Adulto , Idoso , Testes Respiratórios , Monóxido de Carbono/análise , Aconselhamento , Feminino , Hospitalização , Humanos , Masculino , Pessoa de Meia-Idade , Cooperação do Paciente , Prevenção do Hábito de Fumar
10.
Genes Immun ; 3(4): 220-4, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12058257

RESUMO

Nut allergy is an important and potentially life threatening food allergy with a prevalence of one in 150 children in the UK population. STAT6 (signal transducer and activator of transcription) is an important molecule in the induction and regulation of an allergic response, which maps to chromosome 12q in a region previously linked with total serum IgE concentration and atopy in different populations. We have examined the frequency of a single nucleotide polymorphism (SNP) in the 3'UTR region of STAT6 gene in 71 UK Caucasoid patients diagnosed with nut allergy and 45 atopic patients without nut allergy using PCR-RFLP and compared these with 184 UK healthy controls. The STAT6 G allele frequency was significantly increased in nut allergy patients compared with blood donor controls (P < 0.0001, OR = 2.9, 95% CI: 1.7-4.9), which was under a recessive model (GG vs GA+AA, P = 0.0001, OR = 3.2, 95% CI: 1.7-5.8) but not in atopic patients without nut allergy. The G allele was most frequent in the severe cases and GG homozygosity was associated with the increased risk of severe reaction (OR = 3.9, 95% CI: 1.9-8.3). We conclude that STAT6 3'UTR polymorphism is associated with susceptibility and severity in nut allergic patients in our population.


Assuntos
Hipersensibilidade a Noz/genética , Transativadores/genética , Criança , Pré-Escolar , Feminino , Predisposição Genética para Doença , Genótipo , Humanos , Imunoglobulina E/sangue , Masculino , Polimorfismo de Nucleotídeo Único , Fator de Transcrição STAT6 , População Branca/genética
11.
Clin Oncol (R Coll Radiol) ; 14(5): 367-71, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12555875

RESUMO

INTRODUCTION: Small Cell Lung Cancer (SCLC) is increasingly being treated in the district general hospital setting. The search for an active regimen which can be given with the least toxicity and best outcomes led us to use a modified ICE (Ifosfamide, Carboplatin and Etoposide) regimen and modify it further by using oral mesna instead of intravenous mesna. METHOD: All patients selected to receive the modified ICE regime over a 5-year period were included in our study. All patients were assessed for performance status and prognostic factors. Only those with WHO performance status 0-1 and Manchester prognostic score 0-3 were considered for ICE chemotherapy. All patients were followed up for 1 year after recruitment was completed. RESULTS: Median survival for all 32 patients was 18.4 months (CI 12.2-24.6) and for the 28 patients with limited disease the median survival was 19.9 months (CI 8.2-31.6). Toxicity levels were low with no neutropenic deaths. One patient died three days after treatment was started due to disease progression. A total of 6 patients remained alive one year after recruitment was completed. Five out of the 6 were followed up for at least 2 years. CONCLUSION: Using this out-patient modified ICE regime we have achieved a median survival comparable to other active chemotherapy regimes for SCLC with no significant increase in toxicity.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma de Células Pequenas/tratamento farmacológico , Neoplasias Pulmonares/tratamento farmacológico , Administração Oral , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Carboplatina/administração & dosagem , Carcinoma de Células Pequenas/patologia , Etoposídeo/administração & dosagem , Feminino , Humanos , Ifosfamida/administração & dosagem , Neoplasias Pulmonares/patologia , Masculino , Mesna/administração & dosagem , Pessoa de Meia-Idade , Pacientes Ambulatoriais , Prognóstico , Sobrevida
13.
Am J Physiol Regul Integr Comp Physiol ; 280(1): R123-31, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11124142

RESUMO

Diapausing embryos of Austrofundulus limnaeus survive desiccating conditions by reducing evaporative water loss. Over 40% of diapause II embryos survive 113 days of exposure to 75.5% relative humidity. An early loss of water from the perivitelline space occurs during days 1-2, but thereafter, rates of water loss are reduced to near zero. No dehydration of the embryonic tissue is indicated based on microscopic observations and the retention of bulk (freezable) water in embryos as judged by differential scanning calorimetry. Such high resistance to desiccation is unprecedented among aquatic vertebrates. Infrared spectroscopy indicates frequent intermolecular contacts via beta-sheet (14%) in hydrated egg envelopes (chorions). These beta-sheet contacts increase to 36% on dehydration of the egg envelope. Interestingly, the egg envelope is composed of protein fibrils with characteristics of amyloid fibrils usually associated with human disease. These features include a high proportion of intermolecular beta-sheet, positive staining and green birefringence with Congo red, and detection of long, unbranched fibrils with a diameter of 4-6 nm. The high resistance of diapause II embryos to water stress is not correlated with ontogenetic changes in the egg envelope.


Assuntos
Amiloide/metabolismo , Desidratação/metabolismo , Proteínas do Ovo/metabolismo , Embrião não Mamífero/metabolismo , Água/metabolismo , Adaptação Fisiológica/fisiologia , Animais , Varredura Diferencial de Calorimetria , Córion/metabolismo , Dicroísmo Circular , Proteínas do Ovo/análise , Peixes Listrados , Solubilidade , Estresse Fisiológico/metabolismo
14.
Physiol Biochem Zool ; 73(6): 799-808, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11121353

RESUMO

Rates of protein synthesis are substantially depressed in diapause II embryos of Austrofundulus limnaeus. Inhibition of oxygen consumption and heat dissipation with cycloheximide indicates that 36% of the adenosine triphosphate (ATP) turnover in prediapausing embryos (8 d postfertilization [dpf]) is caused by protein synthesis; the contribution of protein synthesis to ATP turnover in diapause II embryos is negligible. In agreement with the metabolic data, incorporation of amino acids (radiolabeled via (14)CO(2)) into perchloric acid-precipitable protein decreases by over 93% in diapause II embryos compared with embryos at 8 dpf. This result represents a 36% reduction in energy demand because of depression of protein synthesis during diapause. Adjusting for changes in the specific radioactivity of the free amino acid pool at the whole-embryo level yields rates of protein synthesis that are artifactually high and not supportable by the observed rates of oxygen consumption and heat dissipation during diapause. This result indicates a regionalized distribution of labeled amino acids likely dictated by a pattern of anterior to posterior cell cycle arrest. AMP/ATP ratios are strongly correlated with the decrease in rates of protein synthesis, which suggests a role for adenosine monophosphate (AMP) in the control of anabolic processes. The major depression of protein synthesis during diapause II affords a considerable reduction in energy demand and extends the duration of dormancy attainable in these embryos.


Assuntos
Peixes Listrados/embriologia , Biossíntese de Proteínas , Aminoácidos/metabolismo , Animais , Cicloeximida/farmacologia , Metabolismo Energético/efeitos dos fármacos , Temperatura Alta , Consumo de Oxigênio/efeitos dos fármacos , Inibidores da Síntese de Proteínas/farmacologia
15.
Am J Physiol Regul Integr Comp Physiol ; 279(6): R2344-8, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11080103

RESUMO

A previous phylogenetic analysis among 15 taxa of the teleost fish Fundulus suggested that there should be thermal-adaptive differences in heart metabolism among populations. To test this hypothesis, the rate of oxygen consumption and the activities of all 11 glycolytic enzymes were measured in isolated heart ventricle from two populations of Fundulus heteroclitus. Heart ventricular metabolism is greater in a northern population versus a southern population of these fish. Analysis of the amount of glycolytic enzymes indicates that 87% of the variation in cardiac metabolism within and between populations is explained by the variation in three enzymes (pyruvate kinase, glyceraldehyde-3-phosphate dehydrogenase, and lactate dehydrogenase). These enzymes are the same three enzymes that were predicted to be important based on previously determined phylogenetic patterns of expression. Our data indicate that near-equilibrium enzymes, as well as classically defined rate-limiting enzymes, can also influence metabolism.


Assuntos
Glicólise , Peixes Listrados/fisiologia , Miocárdio/metabolismo , Aclimatação , Aerobiose , Animais , California , Clima , Gliceraldeído-3-Fosfato Desidrogenases/metabolismo , Ventrículos do Coração , Peixes Listrados/classificação , L-Lactato Desidrogenase/metabolismo , Maine , Contração Miocárdica , Consumo de Oxigênio , Piruvato Quinase/metabolismo , Especificidade da Espécie
16.
Proc Natl Acad Sci U S A ; 97(20): 11080-5, 2000 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-11005877

RESUMO

Mitochondria are confronted with low oxygen levels in the microenvironment within tissues; yet, isolated mitochondria are routinely studied under air-saturated conditions that are effectively hyperoxic, increase oxidative stress, and may impair mitochondrial function. Under hypoxia, on the other hand, respiration and ATP supply are restricted. Under these conditions of oxygen limitation, any compromise in the coupling of oxidative phosphorylation to oxygen consumption could accentuate ATP depletion, leading to metabolic failure. To address this issue, we have developed the approach of oxygen-injection microcalorimetry and ADP-injection respirometry for evaluating mitochondrial function at limiting oxygen supply. Whereas phosphorylation efficiency drops during ADP limitation at high oxygen levels, we show here that oxidative phosphorylation is more efficient at low oxygen than at air saturation, as indicated by higher ratios of ADP flux to total oxygen flux at identical submaximal rates of ATP synthesis. At low oxygen, the proton leak and uncoupled respiration are depressed, thus reducing maintenance energy expenditure. This indicates the importance of low intracellular oxygen levels in avoiding oxidative stress and protecting bioenergetic efficiency.


Assuntos
Mitocôndrias Hepáticas/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Transporte de Elétrons , Hipóxia , Fosforilação , Ratos , Ratos Sprague-Dawley
17.
J Comp Physiol B ; 170(4): 307-14, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10935521

RESUMO

In this study, we compared survivorship, heat dissipation and biochemical features of anaerobiosis of two tiger beetle species (Coleoptera: Cicindelidae) exposed to anoxia. One species commonly experiences environmental immersion from rainfall and snowmelt (Cicindela togata), and the habitat of the other (Amblycheila cylindriformis) is not prone to flooding. The ancestral genus, A. cylindriformis, survives anoxia for only 2 days at 25 degrees C. In response to anoxia, these larvae immediately lose locomotory abilities, tissue concentrations of ATP fall precipitously within 12 h, and significant amounts of lactate are quickly produced. In contrast, C. togata larvae tolerate anoxia for 5 days. Heat dissipation is downregulated to a greater degree than that seen in A. cylindriformis (3.4% versus 14% of standard normoxic rate, respectively), the ability for locomotion is maintained and normoxic levels of ATP are defended for at least 24 h. Lactate is not accumulated until well into anoxic bout, and significant amounts of alanine are also produced. This study provides evidence that tiger beetles differ in physiological responses to anoxia, and that these differences are correlated with flooding risk and with species distribution.


Assuntos
Adaptação Fisiológica/fisiologia , Besouros/metabolismo , Metabolismo Energético/fisiologia , Hipóxia/metabolismo , Difosfato de Adenosina/metabolismo , Monofosfato de Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Anaerobiose/fisiologia , Animais , Desastres , Meio Ambiente , Glicogênio/metabolismo , Temperatura Alta , Inosina Monofosfato/metabolismo , Ácido Láctico/metabolismo , Oxigênio/metabolismo , Filogenia
18.
Immunobiology ; 201(5): 568-82, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10834314

RESUMO

Immature dendritic cells (DC) take up, process and present protein antigens; mature DC are specialized for stimulating primary T cell responses with increased expression of MHC class II and co-stimulatory molecules, but are incapable of processing and presenting soluble protein. The current study examined whether maturation of DC is triggered by T cell recognition of antigens presented by immature DC. Human DC derived from CD34+ progenitor cells by culture with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-6 (IL-6) in serum-free medium could prime naive CD4+ T cells to keyhole limpet hemocyanin (KLH) and ovalbumin (OVA). The cultured DC retained the ability to prime T cells to native protein for at least 15 days. To test for changes in DC function after participation in an immune response, DC were co-cultured with either allogeneic or autologous CD4+ T cells. DC co-cultured with autologous T cells retained the ability to prime T cells to intact protein antigens. By contrast, DC which had previously stimulated an allogeneic T cell response lost ability to prime T cells to soluble proteins. However, such <> induced a MLR and stimulated peptide-specific primary CD4+ T cell responses. This indicated that <> did not die or lose the ability to prime, but lost the ability to process and present subsequent antigens. Following participation in T cell activation, DC increased surface expression of MHC class II, co-stimulatory molecules CD40 and B7.2, and the intercellular adhesion molecule-1 (ICAM-1). In addition, our data suggest that interferon gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) are involved in this T cell-mediated DC maturation.


Assuntos
Apresentação de Antígeno , Células Dendríticas/imunologia , Antígenos de Histocompatibilidade Classe II/análise , Apresentação de Antígeno/imunologia , Antígeno B7-1/análise , Células da Medula Óssea , Linfócitos T CD4-Positivos/imunologia , Antígenos CD40/análise , Comunicação Celular/imunologia , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/imunologia , Células Cultivadas , Técnicas de Cocultura , Meios de Cultura Livres de Soro , Células Dendríticas/efeitos dos fármacos , Fator Estimulador de Colônias de Granulócitos e Macrófagos/farmacologia , Hemocianinas/imunologia , Humanos , Molécula 1 de Adesão Intercelular/análise , Interferon gama/farmacologia , Interleucina-6/farmacologia , Ovalbumina/imunologia , Fatores de Tempo , Fator de Necrose Tumoral alfa/farmacologia
19.
J Comp Physiol B ; 170(2): 125-33, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10791572

RESUMO

Under anoxia, embryos of Artemia franciscana enter a state of quiescence. During this time protein synthesis is depressed, and continued degradation of proteins could jeopardize the ability to recover from quiescence upon return to favorable conditions. In this study, we developed an assay for monitoring ATP/ ubiquitin-dependent proteolysis in order to establish the presence of this degradation mechanism in A. franciscana embryos, and to describe some characteristics that may regulate its function during anoxia-induced quiescence. For lysates experimentally depleted of adenylates, supplementation with ATP and ubiquitin stimulated protein degradation rates by 92 +/- 17% (mean +/- SE) compared to control rates. The stimulation by ATP was maximal at concentrations > or =11 micromol x l(-1). In the presence of ATP and ubiquitin, ubiquitin-conjugated proteins were produced by lysates during the course of the 4-h assays, as detected by Western blotting. Acute acidification of lysates to values approximating the intracellular pH observed under anoxia completely inhibited ATP/ubiquitin-dependent proteolysis. Depressed degradation was also observed under conditions where net ATP hydrolysis occurred. These results suggest that ATP/ubiquitin-dependent proteolysis is markedly inhibited under cellular conditions promoted by anoxia. Inhibition of proteolysis during quiescence may be one critical factor that increases macromolecular stability, which may ultimately govern the duration of embryo survival under anoxia.


Assuntos
Trifosfato de Adenosina/metabolismo , Artemia/metabolismo , Proteínas/metabolismo , Animais , Artemia/embriologia , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Endopeptidases/metabolismo , Concentração de Íons de Hidrogênio , Hidrólise , Hipóxia/metabolismo , Cinética , Proteína Quinase C/metabolismo , Ubiquitinas/metabolismo
20.
J Exp Biol ; 203(Pt 7): 1123-30, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10708633

RESUMO

Transcriptional activity, as assessed by nuclear run-on assays, was constant during 10 h of normoxic development for embryos of the brine shrimp Artemia franciscana. Exposure of embryos to only 4 h of anoxia resulted in a 79.3+/-1 % decrease in levels of in-vivo-initiated transcripts, and transcription was depressed by 88. 2+/-0.7 % compared with normoxic controls after 24 h of anoxia (means +/- s.e.m., N=3). Initiation of transcription was fully restored after 1 h of normoxic recovery. Artificially lowering the intracellular pH of aerobic embryos to the value reflective of anoxia (pH 6.7) showed that acidification alone explained over half the transcriptional arrest. Initiation of transcription was not rescued by application of 80 % carbon monoxide under anoxia, which suggests that heme-based oxygen sensing is not involved in this global arrest. When these transcriptional data are combined with the finding that mRNA levels are unchanged for at least 6 h of anoxia, it is clear that the half-life of mRNA is extended at least 8.5-fold compared with that in aerobic embryos. In contrast to the activation of compensatory mechanisms to cope with anoxia that occurs in mammalian cells, A. franciscana embryos enter a metabolically depressed state in which gene expression and mRNA turnover are cellular costs apparently not compatible with survival and in which extended tolerance supercedes the requirement for continued metabolic function.


Assuntos
Artemia/genética , Artemia/metabolismo , Embrião não Mamífero/metabolismo , Oxigênio/metabolismo , Transcrição Gênica , Animais , Artemia/embriologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
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